The invention relates to looms and more particularly to weft yarn supply systems for looms. It deals particularly with a weft yarn store comprising a drum for taking up a supply of weft yarn; at least one winder for winding weft yarn from a package outside the store onto the drum; and means for retaining the weft yarn at the run-off end of the drum upon termination of picking.
European patent application No. 0 145 163 discloses a weft yarn store which detects the end of picking by a yarn stopper being moved into the path of the departing weft yarn so that departure thereof from the store ceases after a number of turns of yarn have been drawn off from the store. The winder drive is so controlled that a predetermined number of yarn windings are prepared on the drum periphery for each pick. The weft yarn store can meter the weft yarn accurately but yarn length can be varied for picking only in steps corresponding to a peripheral length of the drum. The diameter of the storage drum must be adapted to different weaving widths.
Another weft yarn store, disclosed by European patent application No. 0 107 110, provides an advantage in that it can provide various weft yarn lengths with the use of a constant-diameter drum by providing at the yarn draw-off end of the drum a number of elements for retaining the yarn at the end of picking. Weft yarn length can therefore be varied in steps corresponding to the spacing between the retaining elements on the drum periphery. This kind of store requires numerous mechanical elements to be disposed near the retaining means. The known means do not retain the weft yarn smoothly.